The use of mobile communications devices has become commonplace in today's society. As consumers of mobile communications services become more sophisticated, it becomes more important for service providers to offer more and better services in order to fully meet their subscribers' needs. Such value-added services have become an integral part of the consumer's expectations regarding their mobile communications service.
Many of these value-added services relate to the provision of Intelligent Network (IN) services such as video or music download services, automated call forwarding services, ring-back tone services, prepaid services and the like. In the Global System for Mobile Communications (GSM), the Customized Application of Mobile Enhanced Logic (CAMEL) standard has been developed to aid GSM operators to offer operator-specific services to their subscribers, even if a subscriber is roaming outside their home network. These services can include call processing functions such as caller ID and call screening, call forwarding, call rerouting; charging functions such as location-based charging or personal discounts; and provision of tones and announcements to provide information regarding a call to a subscriber's mobile telephone.
CAMEL protocol is defined in a set of standards established by the ETSI (European Telecommunication Standardization Institute) and later upgraded as part of 3GPP (Third Generation Partnership Project) initiative. These standards can be found at http://webapp.etsi.org/key/queryform.asp and are incorporated by reference herein in their entirety. Additional information regarding CAMEL protocol and operations can be found in many publications. The most comprehensive work on CAMEL including the latest standardization enhancements can be found in the book titled CAMEL, Intelligent Network for the GSM, GPRS and UMTS Networks by Rogier Noldus, published by John, Wiley & Sons Limited (2006). Other publications that describe the architecture and operation of a mobile network using CAMEL functionality include is the publication entitled “Customised Applications for Mobile Enhanced Logic (CAMEL),” by Paulius Meskauskas for the Research Seminar on Nomadic Computing for the Department of Computer Science at the University of Helsinki; the CAMEL tutorial by Zahid Ghadialy entitled “CAMEL: An Introduction,” (Jul. 25, 2004), available on the World Wide Web at http://www.3g4g.co.uk/Tutorial/ZG/zg_camel.html; and “An Introduction to GSM Enhancements for Operator Specific Services (CAMEL)” (1996) by David G. Smith, published by the IEEE, Savoy Place, London. Information regarding CAMEL triggers and trigger detection points may also be found in U.S. Patent documents such as, for example, U.S. Pat. No. 7,050,811 to Grech et al. and U.S. patent application Publication No. 2003/0095566 to Bunting et al. Each of these documents is incorporated by reference herein as to their entirety.
Information regarding CAMEL networks may also be found in U.S. patent application Ser. No. 11/754,808 entitled “Optimized Camel Triggering for Prepaid Calling,” filed May 29, 2007; U.S. patent application Ser. No. 11/765,655 entitled “Conditional Call Treatment For Prepaid Calls,” filed Jun. 20, 2007; and U.S. patent application Ser. No. 11/781,459 filed Jul. 23, 2007, each of which shares at least one common inventor with the present application and each of which is hereby expressly incorporated by reference herein in its entirety.
Processing of a call in a CAMEL network can be accomplished by means of signaling between one or more of a subscriber's Home Location Register (HLR), a visiting Location Register (VLR) associated with the Mobile Switching Center (MSC) where the mobile subscriber is currently located, a Gateway Mobile Switching Center (GMSC), and a Service Control Point (SCP). CAMEL works to enable the provision of enhanced mobile services by providing CAMEL Application Part (CAP) messages, for communication between an SCP and an MSC handling an outgoing call or a GMSC handling an incoming call.
CAMEL also provides a Basic Call State Model (BCSM), which describes the different phases of call processing in the MSC. An Originating Basic Call State Model (O-BCSM) describes the call processing for a mobile-originated call, i.e., a call where the calling party is originating a call from her mobile device. Similarly, a Terminating Basic Call State Model (T-BCSM) describes the call processing to route a terminating call to the mobile subscriber as a recipient of an incoming call. Both the O-BCSM and T-BCSM contain various points in the call processing between the MSC and the SCP. Each state is preceded by a transition step, or Detection Point (DP) where the call is handed over to the SCP for a determination whether the call can proceed to the next state.
Control of a call in a CAMEL network can be managed by the SCP and the MSC or GMSC through the use of DPs (both TDPs and EDPs) and CAP operations. A CAP operation message from the SCP to the MSC can contain instructions regarding the handling of the call at that point or from that point onward. For example, Operation: RequestReportBCSMEvent is used to arm future DPs which contain instructions for future processing. CAP operations also are used to send messages between the MSC and the SCP regarding a status of the call. For example, an operation such as Operation: EventReportBCSMEvent can be used by the MSC to report to the SCP that the call has been answered.
One of the services provided in a CAMEL network is prepaid mobile service, both for mobile originators and mobile recipients of calls in the mobile system. Prepaid mobile service is a popular option for many users. It can enable a user to enjoy the benefits of mobile communications without having to enter into a long-term contract. Prepaid mobile service also can be useful to facilitate management of mobile service. For example, prepaid service can be used to as a parental control tool to manage a child's use of mobile telecommunications services. Prepaid service also can be used by businesses as a management tool to monitor and control corporate use of mobile resources.
CAMEL also can assist in the provision of time-based services in a mobile telecommunications network. For example, a mobile subscriber can receive specialized services from her mobile service provider based on information regarding the subscriber at a particular time or can receive different services depending on whether she is in a particular location at a particular time. Consequently, it can be important to obtain current location and/or local time information regarding the subscriber so that such services can be provided.
One common time-based service is the provision of a different charging schedule for the call depending on the time. Such time-based charging, often embodied in peak/off-peak pricing wherein a call made or received at a “peak” time is charged at a higher rate than one at an “off-peak” time, requires that the SCP and the rating engine, which is part of a Prepaid Platform, have accurate information regarding a time associated with the mobile subscriber, such as the local time of the subscriber and a difference between the subscriber's local time and a standard time such as Greenwich Mean Time. The local time can also decide the eligibility of a subscriber to make or receive a call. For example, a prepaid subscriber may not have sufficient funds in her prepaid account to be eligible to make or receive a call charged at a “peak” rate but may have sufficient funds for an “off-peak” call. Alternatively, parents may want to limit a child's telephone usage during night time or school hours, and so can set their service so that the child's mobile device is ineligible to make or receive all but specific allowed calls during those hours.
There are several ways in which the SCP can obtain local time information at call setup. For a mobile originating call, the MSC where the call is set up can report its local time to the SCP in the CAP operation Initial Detection Point (IDP), irrespective of whether the subscriber is in a CAMEL Phase 2 or Phase 3 system. For a mobile terminating call, however, the process to provide the SCP with the subscriber's local time differs depending on whether the subscriber is in a CAMEL Phase 2 or a CAMEL Phase 3 system. In a CAMEL Phase 3 system, a mobile terminating call can be handled by a Visited MSC where the mobile subscriber is located, and thus also can report its local time to the SCP in the IDP operation.
In a mobile terminating call in a CAMEL Phase 2 system, however, the GMSC which initiates the CAP Dialogue with the SCP does not have information on which time zone the subscriber is currently visiting. Instead, the SCP or Prepaid Platform maintains a database which lists the time zone of each VLR. The database can also list the time zone of each location if the VLR covers more than one time zone. A location can be marked by a Cell Global ID or a Location Area Code, commonly known as LAC in GSM terminology. When the SCP receives the location information in the CAMEL operation IDP, the SCP or Prepaid platform can look up the local time information for this location and calculate the rate and eligibility based on the local time of the subscriber.
It can also be desirable for the SCP to receive updated local time information during the course of the call. For example, a subscriber may begin a call at a time subject to a “peak” charging rate but continue the call to a time subject to an “off-peak” rate. If a moving mobile subscriber remains in a single time zone, for example, the Eastern Standard Time Zone in the Eastern United States, her updated local time at any moment in a call is simply calculated from the call duration. However, a moving mobile subscriber may also move from time zone to time zone during the call, for example, by crossing the state line between Georgia, which is in the Eastern Time Zone, and Alabama, which is in the Central Time Zone. In such a case, the subscriber's local time can change from a time at which a “peak” rate would be charged to an “off-peak” time even if the rate would not change if she remained in a single time zone.
One way the SCP can obtain updated information regarding a mobile subscriber is by a conventional MAP (Mobile Application Part) Any Time Interrogation (ATI) operation. In an ATI operation, the SCP queries the HLR associated with the subscriber for information regarding the subscriber such as subscriber location and subscriber state. The HLR then queries the VLR where the subscriber is registered via a MAP Provide Subscriber Information (PSI) query to obtain information regarding the subscriber. In conventional CAMEL systems, this information can include the identification of the VLR where the subscriber is registered, a Cell Global Identifier, location information such as Geographical Information, and age of the location information. The information provided by the VLR can also include information regarding the subscriber state (e.g., busy, idle, or not available). The VLR returns this information to the HLR via a MAP PSI Response, and the HLR in turn provides this information to the SCP via a MAP ATI Response so that the SCP has up-to-date location and state information regarding a subscriber. SCP or the rating engine can use that information to search the database mentioned earlier to derive the local time and the corresponding time zone information associated with that location.
Another means of obtaining this local time information is described in U.S. patent application Publication No. 2006/0003766 to Parameswar et al. Parameswar describes a method and system for obtaining local time information for use in provision of time-based services. In Parameswar, a query similar to an ATI query is utilized, wherein a servicing entity such as the SCP queries the HLR for the mobile station's current location and time zone information. The HLR in turn queries the mobile station's current VLR for the relevant information and upon receipt of the information from the VLR, transmits the information to the querying servicing entity.
Both of these methods require a query from the SCP to the HLR, a query from the HLR to the VLR, and return messages from the VLR to the HLR and from the HLR to the SCP.
In CAMEL Phase 3, it is possible to also provision a set of information that can control the terminating call at a Visited MSC. This set of information, known as “VT-CSI”, can include the set of TDPs that can intercept the processing of a terminating call towards the subscriber and a set of parameters to control the actions at each of these TDPs. In such a system, the SCP can receive updated location and time information from the VMSC during the call as part of its periodic messaging to the SCP. However, in order for a call to be handled in this way by CAMEL Phase 3, all roaming partners also must be operating using CAMEL Phase 3. If a roaming partner does not have CAMEL Phase 3 but instead has, for example, CAMEL Phase 2, conventional CAMEL call processing does not permit the provision of such local time updates to the SCP.